There have been significant advances in video display technology in recent years. One of the most visually spectacular technological creations of the last decade is the video wall, in which a rectangular array of video display units--television monitors--has the units placed with the pictures nearly contiguous. In this system, the signal, usually from a single video picture, is electronically processed so that a segment of the picture appears on each video screen, the segments being arranged so that the original picture is reconstituted (except for the interstitial margins) in the large on the array of video screens. Some very striking video effects not limited to a single simultaneous picture are also possible, for example, sequencing of images on individual units with partial image changeover so that the transition to a new image appears to occur by sequential replacement of pieces of the picture.
Several patents have disclosed technical improvements useful in the video wall, e.g., Blokland et al., U.S. Pat. No. 4,695,135; Kalua, U.S. Pat. No. 4,866,530. There exist also multi-image video projection systems which produce a slightly overlapped multiple flat image closely analogous to that of the video wall. E.g., Ogino, et al., U.S. Pat. No. 5,011,277. The video wall and its derivatives, however, do not attempt to put the viewer psychologically "inside" the scene or otherwise enhance the sense of dimensionality or the perception of movement in space. The video wall instead produces a very large flat television picture viewable by large live audiences, for example at mass meetings.
Another type of highly technological display currently available is usually referred to as a "virtual reality" system. Although the term "virtual reality" does not have a fixed definition, it most frequently refers to a system in which a computer generates images of an imaginary scene. Typically, computer created images are directed to two display elements inside a headset such that the viewer sees only the computer created images. The images create a stereoscopic illusion of three dimensional space for the viewer, but the images are not "real," that is, they are computer generated, not taken from photographic images. The computational process produces left and right eye perspective images in real time as the observer moves, as though these images were viewed from the virtual location of the observer in the imaginary space. A known application for this technology is to allow an observer to experience what the inside of an architectural space will "feel" like when later constructed. Normally the virtual space which can be viewed is very limited and the process is very computation intensive.
Others, e.g., Naimark, U.S. Pat. No. 4,857,902, issued Aug. 15, 1989, have developed what are referred to as "virtual environment" systems. In a virtual environment system the intent is not to create a perception of three dimensional space so much as it is to give the observer a single flat image which is keyed to a particular location in an actual, but not present, three dimensional scene. The observer may move about in an imaginary way, for example with a mouse keyed to a map, and see what the place looks like from that vantage point, although not with a three dimensional effect. In Naimark, a vast array of images of a particular locale is stored on video disk. The computer is basically a fast look-up device for flat images. The system operates on observer-controlled time, not locked one-to-one with real time.
Yet another class of systems attempts to create a certain sense of dimensionality by placing the viewer inside a projected replica of a surrounding scene. The archetypal example of such a system is the light-point projection system used in a planetarium to create a half-spherical image of the night sky. In most planetaria these images move to represent the observational changes in the night sky over a chosen period of time which is usually a scale time. Much work has also been done with respect to the making and display of hemispherical photograpic images, e.g., McCutchen, U.S. Pat. No. 5,023,725, issued Jun. 11, 1991. Normally neither real time nor real elapsed time, i.e., simulated real time, motion is an element of such displays.
A very recent example of a complex system attempting to create a spatial sense impression potentially involving real time motion is the "surround" display system disclosed in Ritchey, U.S. Pat. No. 5,130,794, issued Jul. 14, 1992. Ritchey discloses a system which appears to be in essence a very large video wall distorted into a spherical surface with the viewer inside. The observer is located on a transparent floor so that the scene appears above and below. This system involves complex image processing to achieve spherical coverage. One application for the Ritchey system is a flight simulator. Another is displaying panoramic images from remotely piloted vehicles (pilotless aircraft). A related system is disclosed in Couturier, U.S. Pat. No. 5,151,802, issued September 29, 1992. Such systems have shared drawbacks in that they are extremely expensive and highly equipment intensive, involve precision engineering, and require a high degree of image processing or computation.
A somewhat similar system also operates in real time but does not particlarly attempt to convey a sense of space. Tuck, U.S. Pat. No. 4,772,942, issued Sep. 20, 1988, discloses a display system with a relatively small cone of viewable space suitable for direct viewing of a scene from inside a military vehicle such as a tank or a submarine. Tuck uses contiguous video display monitors for displaying inside a closed structure an arc of the exterior scene covering less than 90 degrees as events actually happen. This system, though potentially useful in armored weapons systems, undersea vehicles, and simulators, is expensive and complex, has a very limited number of simultaneous viewers, and does not attempt to create an illusion of space. This system also is equipment intensive and requires sensitive matching of image edges.
There has been a felt need for some time, in artistic endeavors, in advertising, in education, in public interest displays, and in entertainment, including home use, of a technically simple, relatively inexpensive system to display moving images to multiple viewers. In particular, there has been a need to display action in such a way that the viewer gets a psychological sense of being surrounded by movement in space without dauntingly expensive equipment.
However, the most important limitation of all of the prior art systems for video display is that they do not take advantage of recent scientific progress in understanding the role of peripheral vision in perceiving motion in space. Such knowledge has proved important in the design of certain aspects of flight simulators, especially in the creation of artificial horizons therein. Morley, U.S. Pat. No. 4,743,903 issued May 10, 1988 and U.S. Pat. No. 4,616,226 issued Oct. 7, 1986, and Malcolm et al., No. 4,397,555 issued Aug. 9, 1983, use the distinction between central focal, or foveal, vision which is acute but limited to a cone of a few degrees about dead ahead, and peripheral vision, which is far less acute but is critical to sensing orientation and motion. Peripheral vision utilizes dedicated cerebral faculties which recognize movement of line features in the peripheral vision field.
Details about the relative movements and positions of objects are conveyed to a specialized portion of the visual cerebral cortex responsible for motion perception. See Semir Zeki, "The Visual Image in Mind and Brain, " Scientific American, September 1992, p. 69. The inherent perceptual function of the human brain of apprehending motion is carried on continuously and automatically and requires no conscious attention. Thus a system which provides information about movement through the peripheral vision field makes use of the dedicated motion perceiving faculties of the visual cerbral cortex which operate below the level of conscious attention, thereby producing an intuitive sensation of motion not subject to conscious control.
It is therefore a first object of the current invention to use the unique properties of the peripheral vision system to provide the desired illusion inexpensively and with technical simplicity. It is a second but also important object of this invention to provide a relatively inexpensive system for display of visual information creating the illusion that the observer is inside a three dimensional space in which movement is taking place relative to the observer, who in turn moves in response to the images.